This application relates to phenylephrine hydrochloride-containing formulations having improved stability and thus increased shelf life.
Phenylephrine hydrochloride (PHL) is a decongestant frequently used in over-the-counter (OTC) cough and cold preparations. PHL is a reactive molecule that undergoes reactions with numerous excipients commonly used in OTC preparations to form other species, with a corresponding decrease in the amount of active PHL in the product. This can lead to a need to set shorter expiration times than may be considered optimum for OTC products.
While many of the reactions of PHL occur at room temperature and conventional indoor humidity conditions, the reaction rates are higher at elevated temperatures and elevated humidity. OTC preparations intended for sale in Climatic Zones with high ambient temperature and humidity (Climatic Zones 3 (30° C./35% relative air humidity) and 4 (30° C./70% or greater relative air humidity) therefore may have significantly shorter shelf life which may make the product unmarketable in these regions.